Background： Prolongation of the Tpeak-Tend （TpTe） interval as a measurement of transmural dispersion of repolarization （TDR） is an independent risk factor for chronic heart failure mortality, However, the cardiac...Background： Prolongation of the Tpeak-Tend （TpTe） interval as a measurement of transmural dispersion of repolarization （TDR） is an independent risk factor for chronic heart failure mortality, However, the cardiac resynchronization therapy＇s （CRT） effect on TDR is controversial. Therefore, this study aimed to evaluate CRTs acute and chronic effects on repolarization dispersion. Furthermore, we aimed to investigate the relationship between TpTe changes and ventricular arrbythmia. Methods： The study group consisted of 101 patients treated with CRT-defibrillator （CRT-D）. According to whether TpTe was shortened, patients were grouped at immediate and l-year follow-up after CRT, respectively. The echocardiogram index and ventricular arrhythmia were observed and compared in these subgroups. Results： For all patients, TpTe slightly increased immediately after CRT-D implantation, and then decreased at the l -year follow-up （from 107 ± 23 to 110 ± 21 rns within 24 h, to 94 ± 24 ms at 1-year follow-up, F 19.366, P 〈 0.001）. No significant difference in the left ventricular reverse remodeling and ventricular tachycardia/ventricular fibrillation （VT/VF） episodes between the TpTe immediately shortened and TpTe immediately nonshortened groups. However, patients in the TpTe at l-year shorten had a higher rate of the lelt ventricular （LV） reverse remodeling （65% vs. 44%, Z2 = 4.495, P - 0.038） and less VT/VF episodes （log-rank test, X2 - 10.207, P = 0.001 ） compared with TpTe I-year nonshortened group. TpTe immediately alter CRT-D independently predicted VT/VF episodes at l-year follow-up （hazard ratio [HR], 1.030; P = 0.001 ）. Conclusions： Patients with TpTe shortened at l -year after CRT had a higher rate of LV reverse remodeling and less VT/VF episodes. The acute changes of TpTe after CRT have minimal value on mechanical reverse remodeling and ventricular arrhythmia.展开更多
AIM: To examine the effect of ibutilide on novel indexes of repolarization in patients with persistent atrial fibrillation (AF). METHODS: We studied consecutive patients scheduled for elective electrical cardioversion...AIM: To examine the effect of ibutilide on novel indexes of repolarization in patients with persistent atrial fibrillation (AF). METHODS: We studied consecutive patients scheduled for elective electrical cardioversion. Intravenous ibutilide (1+1mg) was administered before the electrical cardioversion while close electrocardiographic (ECG) monitoring was performed. ECG indexes such as corrected QT interval (QTc), the interval from the peak until the end of T wave (Tpe), and the Tpe/QT ratio were measured before ibutilide infusion and 10 min after the end of infusion. RESULTS: The final study population consisted of 20 patients (mean age: 67.1±9.9 years, 10 men). Six patients were cardioverted pharmacologically and did not proceed to electrical cardioversion. Two patientsdeveloped short non-sustained episodes of torsades de pointes ventricular tachycardia. All but one of the aforementioned ECG indexes increased significantly after ibutilide administration. In specific, the QTc interval increased from 442 ± 29 to 471 ± 37 ms (P=0.037), the Tpe interval in precordial leads from 96 ms (range 80-108 ms) to 101 ms (range 91-119 ms) (P=0.021), the Tpe interval in lead Ⅱ from 79 ms (range 70-88 ms) to 100 ms (range 87-104 ms) (P<0.001), the Tpe/QT ratio in precordial leads from 0.23 ms (range 0.18-0.26 ms) to 0.26 ms (range 0.23-0.28 ms) (P=0.028), and the Tpe interval dispersion from 25 ms (range 23-30 ms) to 35 ms (range 27-39 ms) (P=0.012). However, the Tpe/QT ratio in lead II did not change significantly. CONCLUSION: Ibutilide increases the duration and dispersion of ventricular repolarization. The prognostic value of Tpe and Tpe/QT in the setting of drug-induced proarrhythmia needs further study.展开更多
Objective:To observe the effects of angiotensin Ⅱ(Ang Ⅱ) pefusion on transmural heterogeneity of Cx43 expression in the rabbit model with acute myocardial ischemia reperfusion(MIR),and investigate the role of rennin...Objective:To observe the effects of angiotensin Ⅱ(Ang Ⅱ) pefusion on transmural heterogeneity of Cx43 expression in the rabbit model with acute myocardial ischemia reperfusion(MIR),and investigate the role of rennin-angiotensin system in malignant ventricular arrhythmia induced by MIR.Methods:Twenty rabbits were randomly divided into MIR group(n=10) and Ang Ⅱ group(n=10).MIR model was produced with traditional ligation and opening of the anterior descending coronary artery in all animal.The hearts in vitro in the MIR group and the Ang Ⅱ group were perfused with simply improved Tyrode's solution and containing Ang Ⅱ Tyrode's solution respectively.90%monophasic action potential repolarization duration,transmural dispersion of repolarization.Cx43 protein(Cx43-pro) and mRNA(Cx43-Cq) expression in subepicardial,midmyocardial and subendocardial myocardium were measured in both groups.The greatest differences of Cx43-pro and Cx43-Cq among three myocardial layers were calculated and shown with △Cx43-pro and △Cx43-Cq respectively.Results:After Ang Ⅱ perfusion,90%monophasic action potential repolarization duration among three myocardial layer were significantly prolonged(P < 0.05 and P < 0.01),and transmural dispersion of repolarization also significantly increased compared with the MIR group(P < 0.05).Compare with the MIR group,three myocardial Cx43-pro and Cx43-Cq expression in the Ang Ⅱ group were significantly decreased(P < 0.05 and P < 0.01).but△Cx43-pro and △Cx43-Cq were significant increased.Conclusions:Renin-angiotensin system increases transmural heterogeneity of Cx43 expression in the rabbit model with MIR by Ang Ⅱ,and enlarge transmural dispersion of repolarization among three myocardial layers of left ventricular which induces malignant ventricular arrhythmia.展开更多
目的研制局部给药跨室壁氯化钾单相动作电位(MAP)记录电极(KC lMAP电极),探讨模拟在体犬交感神经不均一的致心律失常机制。方法由5F动脉鞘管和0.2 mm的绝缘银丝,组构成3对MAP记录电极,鞘芯腔内注入含30%氯化钾琼脂糖凝胶即制成KC lMAP...目的研制局部给药跨室壁氯化钾单相动作电位(MAP)记录电极(KC lMAP电极),探讨模拟在体犬交感神经不均一的致心律失常机制。方法由5F动脉鞘管和0.2 mm的绝缘银丝,组构成3对MAP记录电极,鞘芯腔内注入含30%氯化钾琼脂糖凝胶即制成KC lMAP电极。用自制的电极记录犬左室前壁跨室壁MAP,观察局部异丙肾上腺素对三层心肌细胞动作电位时程(APD)及跨室壁复极离散度(TDR)的影响和心律失常的诱发情况。结果KC lMAP电极能稳定记录三层心肌MAP 120 m in以上,随时间的延长动作电位振幅逐渐降低但不影响复极特性的分析;局部给予异丙肾上腺素(10-5mg/m l)能显著降低中层心肌细胞的APD90(236.9±3.8 m s vs 226.3±3.0 m s)和TDR(35.7±4.8 m s vs 24.9±3.9 m s),中层心肌细胞易于诱发早期后除极及触发活动并引起室性心律失常。结论KC lMAP电极可理想地用于跨室壁心肌复极特性的研究;异丙肾上腺素降低正常犬的TDR,其诱发室性心律失常的机制与后除极和触发活动有关。展开更多
文摘Background： Prolongation of the Tpeak-Tend （TpTe） interval as a measurement of transmural dispersion of repolarization （TDR） is an independent risk factor for chronic heart failure mortality, However, the cardiac resynchronization therapy＇s （CRT） effect on TDR is controversial. Therefore, this study aimed to evaluate CRTs acute and chronic effects on repolarization dispersion. Furthermore, we aimed to investigate the relationship between TpTe changes and ventricular arrbythmia. Methods： The study group consisted of 101 patients treated with CRT-defibrillator （CRT-D）. According to whether TpTe was shortened, patients were grouped at immediate and l-year follow-up after CRT, respectively. The echocardiogram index and ventricular arrhythmia were observed and compared in these subgroups. Results： For all patients, TpTe slightly increased immediately after CRT-D implantation, and then decreased at the l -year follow-up （from 107 ± 23 to 110 ± 21 rns within 24 h, to 94 ± 24 ms at 1-year follow-up, F 19.366, P 〈 0.001）. No significant difference in the left ventricular reverse remodeling and ventricular tachycardia/ventricular fibrillation （VT/VF） episodes between the TpTe immediately shortened and TpTe immediately nonshortened groups. However, patients in the TpTe at l-year shorten had a higher rate of the lelt ventricular （LV） reverse remodeling （65% vs. 44%, Z2 = 4.495, P - 0.038） and less VT/VF episodes （log-rank test, X2 - 10.207, P = 0.001 ） compared with TpTe I-year nonshortened group. TpTe immediately alter CRT-D independently predicted VT/VF episodes at l-year follow-up （hazard ratio [HR], 1.030; P = 0.001 ）. Conclusions： Patients with TpTe shortened at l -year after CRT had a higher rate of LV reverse remodeling and less VT/VF episodes. The acute changes of TpTe after CRT have minimal value on mechanical reverse remodeling and ventricular arrhythmia.
文摘AIM: To examine the effect of ibutilide on novel indexes of repolarization in patients with persistent atrial fibrillation (AF). METHODS: We studied consecutive patients scheduled for elective electrical cardioversion. Intravenous ibutilide (1+1mg) was administered before the electrical cardioversion while close electrocardiographic (ECG) monitoring was performed. ECG indexes such as corrected QT interval (QTc), the interval from the peak until the end of T wave (Tpe), and the Tpe/QT ratio were measured before ibutilide infusion and 10 min after the end of infusion. RESULTS: The final study population consisted of 20 patients (mean age: 67.1±9.9 years, 10 men). Six patients were cardioverted pharmacologically and did not proceed to electrical cardioversion. Two patientsdeveloped short non-sustained episodes of torsades de pointes ventricular tachycardia. All but one of the aforementioned ECG indexes increased significantly after ibutilide administration. In specific, the QTc interval increased from 442 ± 29 to 471 ± 37 ms (P=0.037), the Tpe interval in precordial leads from 96 ms (range 80-108 ms) to 101 ms (range 91-119 ms) (P=0.021), the Tpe interval in lead Ⅱ from 79 ms (range 70-88 ms) to 100 ms (range 87-104 ms) (P<0.001), the Tpe/QT ratio in precordial leads from 0.23 ms (range 0.18-0.26 ms) to 0.26 ms (range 0.23-0.28 ms) (P=0.028), and the Tpe interval dispersion from 25 ms (range 23-30 ms) to 35 ms (range 27-39 ms) (P=0.012). However, the Tpe/QT ratio in lead II did not change significantly. CONCLUSION: Ibutilide increases the duration and dispersion of ventricular repolarization. The prognostic value of Tpe and Tpe/QT in the setting of drug-induced proarrhythmia needs further study.
文摘[目的]分析肥厚型心肌病患者T波峰-末间期(Tpeak-Tend interval,Tpe)的特点,探讨Tpe在评价心室复极离散度中的意义。[方法]对已确诊的原发性肥厚型心肌病21例及正常人19例进行回顾性分析。测量体表心电图12个导联的Tpe和QT间期离散度(dispersion of QT interval,QTd),T波低平的导联除外,计算Tpe平均值校正值(Tpe-AVEC)、Tpe最大值校正值(Tpe-MAXC)、V1导联Tpe校正值(Tpe-V1C)、V5导联Tpe校正值(Tpe-V5C)、Ⅱ导Tpe校正值(Tpe-ⅡC)。比较上述各参数在肥厚型心肌病与正常人之间的差异。[结果]肥厚型心肌病组与正常对照组比较:Tpe-AVEC(91.3±13.1)vs(2.7±10.0),P=0.026、Tpe-MAXC(154.7±31.5)vs(19.2±11.6),P=0、Tpe-ⅡC(93.6±34.1)vs(2.5±13.5),P=0.017、QTd(59.1±21.3)vs(9.7±17.0),P=0.003、Tpe-V1C(94.6±26.2)vs(7.2±21.2),P=0.382、Tpe-V5C(89.0±20.9)vs(6.9±12.7),P=0.704。肥厚型心肌病组Tpe-AVEC、Tpe-MAXC、Tpe-ⅡC、QTd与正常对照组比较差异有显著性意义(P<0.05),而Tpe-V1C、Tpe-V5C与正常对照组比较差异无显著性意义。[结论]Tpe反映心室整体复极离散度的可能性大。在Tpe测量中建议选用Tpe-AVE、Tpe-MAX和Tpe-Ⅱ,可能更适用于评价该类患者的心室复极离散。
基金supported by National Natural Science Foundation of China(NO.81160024)Natural Science Foundation of Hainan Province(NO.814371)
文摘Objective:To observe the effects of angiotensin Ⅱ(Ang Ⅱ) pefusion on transmural heterogeneity of Cx43 expression in the rabbit model with acute myocardial ischemia reperfusion(MIR),and investigate the role of rennin-angiotensin system in malignant ventricular arrhythmia induced by MIR.Methods:Twenty rabbits were randomly divided into MIR group(n=10) and Ang Ⅱ group(n=10).MIR model was produced with traditional ligation and opening of the anterior descending coronary artery in all animal.The hearts in vitro in the MIR group and the Ang Ⅱ group were perfused with simply improved Tyrode's solution and containing Ang Ⅱ Tyrode's solution respectively.90%monophasic action potential repolarization duration,transmural dispersion of repolarization.Cx43 protein(Cx43-pro) and mRNA(Cx43-Cq) expression in subepicardial,midmyocardial and subendocardial myocardium were measured in both groups.The greatest differences of Cx43-pro and Cx43-Cq among three myocardial layers were calculated and shown with △Cx43-pro and △Cx43-Cq respectively.Results:After Ang Ⅱ perfusion,90%monophasic action potential repolarization duration among three myocardial layer were significantly prolonged(P < 0.05 and P < 0.01),and transmural dispersion of repolarization also significantly increased compared with the MIR group(P < 0.05).Compare with the MIR group,three myocardial Cx43-pro and Cx43-Cq expression in the Ang Ⅱ group were significantly decreased(P < 0.05 and P < 0.01).but△Cx43-pro and △Cx43-Cq were significant increased.Conclusions:Renin-angiotensin system increases transmural heterogeneity of Cx43 expression in the rabbit model with MIR by Ang Ⅱ,and enlarge transmural dispersion of repolarization among three myocardial layers of left ventricular which induces malignant ventricular arrhythmia.
文摘目的研制局部给药跨室壁氯化钾单相动作电位(MAP)记录电极(KC lMAP电极),探讨模拟在体犬交感神经不均一的致心律失常机制。方法由5F动脉鞘管和0.2 mm的绝缘银丝,组构成3对MAP记录电极,鞘芯腔内注入含30%氯化钾琼脂糖凝胶即制成KC lMAP电极。用自制的电极记录犬左室前壁跨室壁MAP,观察局部异丙肾上腺素对三层心肌细胞动作电位时程(APD)及跨室壁复极离散度(TDR)的影响和心律失常的诱发情况。结果KC lMAP电极能稳定记录三层心肌MAP 120 m in以上,随时间的延长动作电位振幅逐渐降低但不影响复极特性的分析;局部给予异丙肾上腺素(10-5mg/m l)能显著降低中层心肌细胞的APD90(236.9±3.8 m s vs 226.3±3.0 m s)和TDR(35.7±4.8 m s vs 24.9±3.9 m s),中层心肌细胞易于诱发早期后除极及触发活动并引起室性心律失常。结论KC lMAP电极可理想地用于跨室壁心肌复极特性的研究;异丙肾上腺素降低正常犬的TDR,其诱发室性心律失常的机制与后除极和触发活动有关。
